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[dragonfly.git] / sys / netinet / ip_encap.c
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1 /* $FreeBSD: src/sys/netinet/ip_encap.c,v 1.1.2.5 2003/01/23 21:06:45 sam Exp $ */
2 /* $DragonFly: src/sys/netinet/ip_encap.c,v 1.15 2006/09/05 00:55:48 dillon Exp $ */
3 /* $KAME: ip_encap.c,v 1.41 2001/03/15 08:35:08 itojun Exp $ */
5 /*
6 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7 * All rights reserved.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the project nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
34 * My grandfather said that there's a devil inside tunnelling technology...
36 * We have surprisingly many protocols that want packets with IP protocol
37 * #4 or #41. Here's a list of protocols that want protocol #41:
38 * RFC1933 configured tunnel
39 * RFC1933 automatic tunnel
40 * RFC2401 IPsec tunnel
41 * RFC2473 IPv6 generic packet tunnelling
42 * RFC2529 6over4 tunnel
43 * mobile-ip6 (uses RFC2473)
44 * RFC3056 6to4 tunnel
45 * isatap tunnel
46 * Here's a list of protocol that want protocol #4:
47 * RFC1853 IPv4-in-IPv4 tunnelling
48 * RFC2003 IPv4 encapsulation within IPv4
49 * RFC2344 reverse tunnelling for mobile-ip4
50 * RFC2401 IPsec tunnel
51 * Well, what can I say. They impose different en/decapsulation mechanism
52 * from each other, so they need separate protocol handler. The only one
53 * we can easily determine by protocol # is IPsec, which always has
54 * AH/ESP/IPComp header right after outer IP header.
56 * So, clearly good old protosw does not work for protocol #4 and #41.
57 * The code will let you match protocol via src/dst address pair.
59 /* XXX is M_NETADDR correct? */
61 #include "opt_inet.h"
62 #include "opt_inet6.h"
64 #include <sys/param.h>
65 #include <sys/systm.h>
66 #include <sys/socket.h>
67 #include <sys/sockio.h>
68 #include <sys/mbuf.h>
69 #include <sys/errno.h>
70 #include <sys/protosw.h>
71 #include <sys/queue.h>
73 #include <net/if.h>
74 #include <net/route.h>
76 #include <netinet/in.h>
77 #include <netinet/in_systm.h>
78 #include <netinet/ip.h>
79 #include <netinet/ip_var.h>
80 #include <netinet/ip_encap.h>
82 #ifdef INET6
83 #include <netinet/ip6.h>
84 #include <netinet6/ip6_var.h>
85 #include <netinet6/ip6protosw.h>
86 #endif
88 #include <machine/stdarg.h>
90 #include <net/net_osdep.h>
92 #include <sys/kernel.h>
93 #include <sys/malloc.h>
94 #include <sys/thread2.h>
95 MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
97 static void encap_add (struct encaptab *);
98 static int mask_match (const struct encaptab *, const struct sockaddr *,
99 const struct sockaddr *);
100 static void encap_fillarg (struct mbuf *, const struct encaptab *);
102 #ifndef LIST_HEAD_INITIALIZER
103 /* rely upon BSS initialization */
104 LIST_HEAD(, encaptab) encaptab;
105 #else
106 LIST_HEAD(, encaptab) encaptab = LIST_HEAD_INITIALIZER(&encaptab);
107 #endif
109 void (*ipip_input)(struct mbuf *, int, int); /* hook for mrouting */
111 void
112 encap_init(void)
114 static int initialized = 0;
116 if (initialized)
117 return;
118 initialized++;
119 #if 0
121 * we cannot use LIST_INIT() here, since drivers may want to call
122 * encap_attach(), on driver attach. encap_init() will be called
123 * on AF_INET{,6} initialization, which happens after driver
124 * initialization - using LIST_INIT() here can nuke encap_attach()
125 * from drivers.
127 LIST_INIT(&encaptab);
128 #endif
131 #ifdef INET
132 void
133 encap4_input(struct mbuf *m, ...)
135 int off, proto;
136 struct ip *ip;
137 struct sockaddr_in s, d;
138 const struct protosw *psw;
139 struct encaptab *ep, *match;
140 int prio, matchprio;
141 __va_list ap;
143 __va_start(ap, m);
144 off = __va_arg(ap, int);
145 proto = __va_arg(ap, int);
146 __va_end(ap);
148 ip = mtod(m, struct ip *);
150 bzero(&s, sizeof s);
151 s.sin_family = AF_INET;
152 s.sin_len = sizeof(struct sockaddr_in);
153 s.sin_addr = ip->ip_src;
154 bzero(&d, sizeof d);
155 d.sin_family = AF_INET;
156 d.sin_len = sizeof(struct sockaddr_in);
157 d.sin_addr = ip->ip_dst;
159 match = NULL;
160 matchprio = 0;
161 for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) {
162 if (ep->af != AF_INET)
163 continue;
164 if (ep->proto >= 0 && ep->proto != proto)
165 continue;
166 if (ep->func)
167 prio = (*ep->func)(m, off, proto, ep->arg);
168 else {
170 * it's inbound traffic, we need to match in reverse
171 * order
173 prio = mask_match(ep, (struct sockaddr *)&d,
174 (struct sockaddr *)&s);
178 * We prioritize the matches by using bit length of the
179 * matches. mask_match() and user-supplied matching function
180 * should return the bit length of the matches (for example,
181 * if both src/dst are matched for IPv4, 64 should be returned).
182 * 0 or negative return value means "it did not match".
184 * The question is, since we have two "mask" portion, we
185 * cannot really define total order between entries.
186 * For example, which of these should be preferred?
187 * mask_match() returns 48 (32 + 16) for both of them.
188 * src=3ffe::/16, dst=3ffe:501::/32
189 * src=3ffe:501::/32, dst=3ffe::/16
191 * We need to loop through all the possible candidates
192 * to get the best match - the search takes O(n) for
193 * n attachments (i.e. interfaces).
195 if (prio <= 0)
196 continue;
197 if (prio > matchprio) {
198 matchprio = prio;
199 match = ep;
203 if (match) {
204 /* found a match, "match" has the best one */
205 psw = match->psw;
206 if (psw && psw->pr_input) {
207 encap_fillarg(m, match);
208 (*psw->pr_input)(m, off, proto);
209 } else
210 m_freem(m);
211 return;
214 /* for backward compatibility */
215 if (proto == IPPROTO_IPV4 && ipip_input) {
216 ipip_input(m, off, proto);
217 return;
220 /* last resort: inject to raw socket */
221 rip_input(m, off, proto);
223 #endif
225 #ifdef INET6
227 encap6_input(struct mbuf **mp, int *offp, int proto)
229 struct mbuf *m = *mp;
230 struct ip6_hdr *ip6;
231 struct sockaddr_in6 s, d;
232 const struct ip6protosw *psw;
233 struct encaptab *ep, *match;
234 int prio, matchprio;
236 ip6 = mtod(m, struct ip6_hdr *);
238 bzero(&s, sizeof s);
239 s.sin6_family = AF_INET6;
240 s.sin6_len = sizeof(struct sockaddr_in6);
241 s.sin6_addr = ip6->ip6_src;
242 bzero(&d, sizeof d);
243 d.sin6_family = AF_INET6;
244 d.sin6_len = sizeof(struct sockaddr_in6);
245 d.sin6_addr = ip6->ip6_dst;
247 match = NULL;
248 matchprio = 0;
249 for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) {
250 if (ep->af != AF_INET6)
251 continue;
252 if (ep->proto >= 0 && ep->proto != proto)
253 continue;
254 if (ep->func)
255 prio = (*ep->func)(m, *offp, proto, ep->arg);
256 else {
258 * it's inbound traffic, we need to match in reverse
259 * order
261 prio = mask_match(ep, (struct sockaddr *)&d,
262 (struct sockaddr *)&s);
265 /* see encap4_input() for issues here */
266 if (prio <= 0)
267 continue;
268 if (prio > matchprio) {
269 matchprio = prio;
270 match = ep;
274 if (match) {
275 /* found a match */
276 psw = (const struct ip6protosw *)match->psw;
277 if (psw && psw->pr_input) {
278 encap_fillarg(m, match);
279 return (*psw->pr_input)(mp, offp, proto);
280 } else {
281 m_freem(m);
282 return IPPROTO_DONE;
286 /* last resort: inject to raw socket */
287 return rip6_input(mp, offp, proto);
289 #endif
291 static void
292 encap_add(struct encaptab *ep)
295 LIST_INSERT_HEAD(&encaptab, ep, chain);
299 * sp (src ptr) is always my side, and dp (dst ptr) is always remote side.
300 * length of mask (sm and dm) is assumed to be same as sp/dp.
301 * Return value will be necessary as input (cookie) for encap_detach().
303 const struct encaptab *
304 encap_attach(int af, int proto, const struct sockaddr *sp,
305 const struct sockaddr *sm, const struct sockaddr *dp,
306 const struct sockaddr *dm, const struct protosw *psw, void *arg)
308 struct encaptab *ep;
309 int error;
311 crit_enter();
312 /* sanity check on args */
313 if (sp->sa_len > sizeof ep->src || dp->sa_len > sizeof ep->dst) {
314 error = EINVAL;
315 goto fail;
317 if (sp->sa_len != dp->sa_len) {
318 error = EINVAL;
319 goto fail;
321 if (af != sp->sa_family || af != dp->sa_family) {
322 error = EINVAL;
323 goto fail;
326 /* check if anyone have already attached with exactly same config */
327 for (ep = LIST_FIRST(&encaptab); ep; ep = LIST_NEXT(ep, chain)) {
328 if (ep->af != af)
329 continue;
330 if (ep->proto != proto)
331 continue;
332 if (ep->src.ss_len != sp->sa_len ||
333 bcmp(&ep->src, sp, sp->sa_len) != 0 ||
334 bcmp(&ep->srcmask, sm, sp->sa_len) != 0)
335 continue;
336 if (ep->dst.ss_len != dp->sa_len ||
337 bcmp(&ep->dst, dp, dp->sa_len) != 0 ||
338 bcmp(&ep->dstmask, dm, dp->sa_len) != 0)
339 continue;
341 error = EEXIST;
342 goto fail;
345 ep = kmalloc(sizeof *ep, M_NETADDR, M_INTWAIT | M_ZERO | M_NULLOK);
346 if (ep == NULL) {
347 error = ENOBUFS;
348 goto fail;
351 ep->af = af;
352 ep->proto = proto;
353 bcopy(sp, &ep->src, sp->sa_len);
354 bcopy(sm, &ep->srcmask, sp->sa_len);
355 bcopy(dp, &ep->dst, dp->sa_len);
356 bcopy(dm, &ep->dstmask, dp->sa_len);
357 ep->psw = psw;
358 ep->arg = arg;
360 encap_add(ep);
362 error = 0;
363 crit_exit();
364 return ep;
366 fail:
367 crit_exit();
368 return NULL;
371 const struct encaptab *
372 encap_attach_func(int af, int proto,
373 int (*func)(const struct mbuf *, int, int, void *),
374 const struct protosw *psw, void *arg)
376 struct encaptab *ep;
377 int error;
379 crit_enter();
380 /* sanity check on args */
381 if (!func) {
382 error = EINVAL;
383 goto fail;
386 ep = kmalloc(sizeof *ep, M_NETADDR, M_INTWAIT | M_ZERO | M_NULLOK);
387 if (ep == NULL) {
388 error = ENOBUFS;
389 goto fail;
392 ep->af = af;
393 ep->proto = proto;
394 ep->func = func;
395 ep->psw = psw;
396 ep->arg = arg;
398 encap_add(ep);
400 error = 0;
401 crit_exit();
402 return ep;
404 fail:
405 crit_exit();
406 return NULL;
410 encap_detach(const struct encaptab *cookie)
412 const struct encaptab *ep = cookie;
413 struct encaptab *p;
415 for (p = LIST_FIRST(&encaptab); p; p = LIST_NEXT(p, chain)) {
416 if (p == ep) {
417 LIST_REMOVE(p, chain);
418 kfree(p, M_NETADDR); /*XXX*/
419 return 0;
423 return EINVAL;
426 static int
427 mask_match(const struct encaptab *ep, const struct sockaddr *sp,
428 const struct sockaddr *dp)
430 struct sockaddr_storage s;
431 struct sockaddr_storage d;
432 int i;
433 const u_int8_t *p, *q;
434 u_int8_t *r;
435 int matchlen;
437 if (sp->sa_len > sizeof s || dp->sa_len > sizeof d)
438 return 0;
439 if (sp->sa_family != ep->af || dp->sa_family != ep->af)
440 return 0;
441 if (sp->sa_len != ep->src.ss_len || dp->sa_len != ep->dst.ss_len)
442 return 0;
444 matchlen = 0;
446 p = (const u_int8_t *)sp;
447 q = (const u_int8_t *)&ep->srcmask;
448 r = (u_int8_t *)&s;
449 for (i = 0 ; i < sp->sa_len; i++) {
450 r[i] = p[i] & q[i];
451 /* XXX estimate */
452 matchlen += (q[i] ? 8 : 0);
455 p = (const u_int8_t *)dp;
456 q = (const u_int8_t *)&ep->dstmask;
457 r = (u_int8_t *)&d;
458 for (i = 0 ; i < dp->sa_len; i++) {
459 r[i] = p[i] & q[i];
460 /* XXX rough estimate */
461 matchlen += (q[i] ? 8 : 0);
464 /* need to overwrite len/family portion as we don't compare them */
465 s.ss_len = sp->sa_len;
466 s.ss_family = sp->sa_family;
467 d.ss_len = dp->sa_len;
468 d.ss_family = dp->sa_family;
470 if (bcmp(&s, &ep->src, ep->src.ss_len) == 0 &&
471 bcmp(&d, &ep->dst, ep->dst.ss_len) == 0) {
472 return matchlen;
473 } else
474 return 0;
477 static void
478 encap_fillarg(struct mbuf *m, const struct encaptab *ep)
480 struct m_tag *tag;
482 tag = m_tag_get(PACKET_TAG_ENCAP, sizeof(void *), MB_DONTWAIT);
483 if (tag != NULL) {
484 *(void **)m_tag_data(tag) = ep->arg;
485 m_tag_prepend(m, tag);
489 void *
490 encap_getarg(struct mbuf *m)
492 void *p = NULL;
493 struct m_tag *tag;
495 tag = m_tag_find(m, PACKET_TAG_ENCAP, NULL);
496 if (tag != NULL) {
497 p = *(void **)m_tag_data(tag);
498 m_tag_delete(m, tag);
500 return p;